The inventor's prior U.S. Pat. No, 5,120,480, describes techniques for making insulated containers of incrementally different sizes and shapes. The containers consist of an inner shell and an outer shell of glass fiber reinforced resin with an insulating foam poured between the shells. Each of the shells is formed upon a mold by laying up glass fibers, either in mat or in chopped fiber form, and resin upon the mold surface in conventional manner. Each mold is formed of assembled elements so as to allow the dimensions of tile mold, and hence the shell, to be incrementally varied. That technique allows the economical production of insulated containers of non metallic construction having a wide range of customized sizes and shapes.
It is necessary to provide a heat extracting means within an insulated container in order for the container to function as the cabinet for a refrigerator or freezer. Such heat extracting means typically comprise an evaporator plate supplied by a refrigerant compressor. Evaporator plate assemblies typically comprise either a plate-type heat exchanger with fluid passageways formed between a pair of metal sheets, or a metal plate having a coil of metal tubing attached thereto. Evaporator plates having set dimensions are commercially available, and are typically installed within the cabinet against one of its inner side walls. In order to obtain adequate performance, the size and shape of the evaporator plate must be matched to the size and shape of the cabinet, or insulated container, to which it is fitted.
Commercially available evaporator plate assemblies come only in a limited number of sizes and shapes, thus severely restricting the variety of size and shape options available to a manufacturer of custom fitted units. Furthermore, an evaporator plate assembly inserted into a refrigerated container has a number of other limitations and drawbacks. In refrigerated containers of usual dimension, long and narrow for example, it is difficult to obtain a rapid initial cool-down and maintain an acceptable temperature profile throughout the container. Because an evaporator plate assembly that is inserted into a refrigerated container is exposed directly to the contents placed in the container, there is always the possibility of physical damage. Also, there is a continuing potential for corrosion of an exposed plate assembly in a marine environment.
Refrigerators and freezers, such as those typically used in a home, use condensing coils to discard heat from the refrigeration process into the atmosphere. Those condensing coils lave conventionally been placed on the outside of the refrigerator cabinet, at the rear thereof. Recent refrigerator designs attach the condensing coils to the inside surface of the outer metal cabinet wall. The metal wall transmits heat from the condensing coils, and provides heat exchange surface to discharge heat into the atmosphere. An example of that type of condensing coil design is shown in a patent to Borghi, U.S. Pat. No. 3,520,581. The condensing coils used by Borghi are of semicircular cross-section, with a flat side which is held against the inner surface of the outer cabinet wall by means of adhesive tape. A recent patent to Patterson, U.S. Pat. No. 5,154,792, discloses certain urethane polymers which exhibit good heat transfer properties and thermal stability. The polymers are used to join cooling and condensing tubes to a metal panel.
Despite the recent advances in designs and materials, there has not been available refrigerant evaporator systems that are adaptable for use in the manufacture of custom sized and shaped refrigerated containers. This invention fills that need.